Anybody else having trouble with modelmaster enamel going bad in bottle?

Happens to me all the time. Fortunately, I don't use MM enamels too often.

It also happens to me but not always. Unused but old bottles remain fresh and usable but somewhat used ones sometimes turn to glop. I suspect the problem is related to the bottle caps and the lousy paper gasket that Testors uses that may not seal properly. When I'm diligent enough to try to clean the bottle threads and the cap I get better results but not always. That's why I like Tamiya's bottles although not the paint. There's a plastic gasket in the cap that seals and yet doesn't get so stuck I need pliers to open the bottle. 

I stopped using MM awhile ago but my hobby shop guy said to make sure the top and threads are clean of paint and turn the bottles upside down. Not really sure if it works....

As long as you keep the threads on the bottle clean, it should last you a long time.

Yes it happens to me too. I used to put back in the bottle left over paint from an AB session and noticed that soon afterwards the paint went bad. I believe it may be the generic paint thinner from Home Depot I was using at the time. I stopped using it and got the Testors thinner in the red can to thin MM enamels. I noticed that even after dumping back leftover paint in the bottle the problem has stopped. So therefore the generic thinner may have contributed to degrading the paint quality.

I have a couple of MM enamel bottles that are way over 10-12 years old and are just as fresh like the first day I got them. Keeping the bottle threads and lip clean of paint will insure a good seal. I also do not shake but rather stir the paint, which keeps it off the cap and upper bottle area. 

It's hit or miss.  Some bottles sit for years with no problem.  Others go bad in months.  I think it's the fragile paper seal.  I've done a few experiments.  One was to put a mini marsmallow in an empty Testors bottle, close it and put it in a small vacuum chamber.  The marshmallow swelled to about twice size.  Then I released the vacuum.  Some bottles would stay the same, while in others the marshmallow would immediately pop back to normal.

The paper seal has no rebound.  Once it's crushed, it stays crushed. Any irregularity and it will leak.  I've tried different materials for the seal with my vacuum test and the best I've found so far is thin rubber packing sheet that I got at Home Depot. It's a bother to cut out little circles, but the lids can be re-used.

Here's something you could try.  Clean the lid and threads of a bottle of paint and screw the lid on tight.  Now, put it inside another container with a lid, something like an empty peanut butter jar.  Let it sit for a day and then open the jar and smell.  If you smell paint, the seal is leaking.

I heard from one guy who keeps his paints in a small refrigerator.  That makes sense.  Cooling reduces the vapor pressure of the solvents and slows evaporation.

Testors could probably come up with a better seal, but why would they want to do that?

Don

Exposure to heat affects it. Probably evaporates the solvent in the paint.

Every bottle of testors I've had has mucked up to thick oatmeal consistency w in a few months of having them. Plus when you take the cap off it has a film on bottle opening. Tamiya and Vallejo are my go to's now.

Ive had the same experience for the past several years also. I’ll open a bottle, stir it thoroughly, and transfer paint out to airbrush or palette for use. The threads are kept clean and no thinner in a brush or other such possible source of contamination is introduced into the bottle. After that I close up the jar as tight as possible by hand. Yet when I go back to use that same jar months or years later, it is un usable goop.

In my view it’s a quality control issue on their part. This did not used to happen with their paints. And at nearly $4 a bottle at shops nowadays, replacing multiple colors is not cheap. Best solution in my experience- Humbrol enamels.

Yes me too not very often I have just started modeling again my MM paints have been setting unsed since last April. So far so good no jelly yet,every time I loose one it seams to always be the same color. Wood and gunmetel, I started keeping the bottlenecks and the lids clean seams my loses have decreased. No probluems with my Tamyia colors as yet I have noticed a second seal on the Tamyia bottles when I close.              ACESES5

Been using MM enamels for YEARS now...and have noticed certain colors seem to be much more prone to turning sour in short order. The worst luck I have had has been with RLM02 and any shades of blue. I have yet to get to the bottom of a bottle for those colors...not that they get a lot of use. 

Hey, Chris, Really good question. It's a real irritation when you get ready to paint and find out the color you needed is dried up! I think some paint colors tend to turn solid faster than others. Maybe it has something to do with the different pigments that are used to create the different colors. If it's just a seal problem, try putting some plumbers teflon tape on the threads of the bottle and screwing the cap down onto that. That should ensure an airtight seal. After all, the tape stops water leaks, and nothing is harder to stop than water. Water will find a way to leak from a connection if it's at all possible. Teflon tape is great for that. The tape is very thin and doesn't have a lot of grab, so you can still open your bottles pretty easily. Apply the tape clockwise (left-to-right) so that the cap screws down onto it in the same direction the tape was wrapped on. You may want to put new tape on after each use. You can buy a spool of it at any hardware store for a couple dollars and it will last forever for your needs. Barrett

Like everyone else yes I have.  It does seem to be either certain colors, or maybe just the newer ones I've bought because I have some that were purchased and opened 20+ years ago that I'm still using now.  But I rarely have issues with the little Testors square bottles.  Maybe I'll take Stik's advice and look at Humbrol.  They do carry it at the nearest LHS.

Dave

Dave, Humbrol enamels will last forever. They're in metal pots with tight fitting lids, but you do need to make sure you seat the lids really well. Then store them upside down for some extra protection. They can be messy opening them up, though. I suggest staying away from Humbrol acrylics. I don't know of anything that dries out faster in the pot than Humbrol acylics. If I buy one because it's the only one with the color I want, I open it in the store to make sure it's still good. No sense in going home and finding that out. I went through a half dozen bottles once and finally gave up. By then, the clerk was really irritated at me anyway. I think the display was old, but nevertheless, these were pots that had never been opened and they were so dried out that you couldn't even get them to pour.  Barrett

I find the problem on bottles that I have opened and used.  Unopened ones seem to last a fair time, but once I have opened them and stirred them, I find they do go bad fairly fast.

Don Stauffer

I find the problem on bottles that I have opened and used.  Unopened ones seem to last a fair time, but once I have opened them and stirred them, I find they do go bad fairly fast.

 

Hit-n-miss with this stuff...some last years and some last weeks/months.

once open I try to shake them once a month.  it dose help. I also go through my kits that I have opened and spray parts on the trees. I mostly do this with RLM66 and aircraft interior green. I just read a article yesterday that once open this person put plastic wrap over the bottle healed and sealed with a rubber band.

Really, I have a bottle of RLM blue that I opened a couple of years ago, and it's still good to go, however Aircraft interior black went bad, go figure...